Sustainable Worm Control Strategies for Sheep. LSSC Ltd

Sustainable Worm Control Strategies for Sheep LSSC Ltd

Sustainable Worm Control Strategies for Sheep This slide show has been made available by SCOPS SCOPS is an industry-wide initiative including representation from: NSA; NOAH; RUMA; CSL; SVS; RVC; SAC; SNFU; AHDA; Defra

Three Main Changes The Sheep Industry The Parasites The Anthelmintics and Resistance

Changes in the Sheep Industry 40% increase in sheep numbers since 1980 25 % reduction in cattle numbers 25% reduction in temporary grass area 30% reduction in labour available

Implications For Worm Control Loss of opportunity for alternation and/or new leys More continuous sheep grazing at higher stocking rates More sheep/shepherd - Blueprint control strategies Increasing reliance on anthelmintics

Blueprint Control Strategies Convenient Prophylactic Easily planned and recorded Effective historically Relatively cheap Rely on highly effective anthelmintics LSSC Ltd

Changes in Parasites - examples 1.Haemonchus contortus - more widespread 2.Trichostrongylus earlier 3.Nematodirus in the autumn

The Anthelmintics ML group added Persistency Resistance No new groups in foreseeable future LSSC Ltd

Three Broad Spectrum Groups Broad Spectrum Anthelmintics Group 1 (BZ) Benzimidazoles White drenches Group 2 (LM) Levamisoles Yellow drenches Group 3 (ML) Macrocyclic-lactones Clear drenches

What is Resistance? Resistance is the heritable ability of the parasite to tolerate a normally effective dose of the anthelmintic. FECRT reduction less than 95%.but you will probably not notice there is a problem until the reduction is much less than 95%

Moredun Survey - % BZ Resistance on Farms 90 80 70 60 Average 2000 50 40 30 Average 1991 20 10 0 Lowland Upland Hill

Frequency The Rate AR Appears in a Flock Alleles Homozygous resistant worms 1.0 0.8 0.6 C 0.4 B 0.2 0.0 A Time

The 8 New Recommendations Work out a control strategy with your veterinarian or advisor. Use effective quarantine strategies to prevent the importation of resistant worms in introduced sheep and goats Test for AR on your farm Administer anthelmintics effectively

The 8 New Recommendations Use anthelmintics only when necessary Select the appropriate anthelmintic for the task Adopt strategies to preserve susceptible worms on the farm Reduce dependence on anthelmintics

1. Have a Strategy Work out a control strategy Develop a cost effective, reliable and sustainable plan.

2. Treat Sheep in Quarantine Treat with an ML and an LM sequentially Hold off pasture for 24-48 hours Turn out on to dirty pasture

3. Test for AR on Your Farm Post drench efficacy tests FECRTs Larval development tests LSSC

4. Administer Anthelmintics Effectively Dose for the heaviest in the group Check the dosing gun Restrict feed (BZ + ML) Use correct technique

Correct Dosing Technique Ensure the drench goes over the back of the tongue

5. Dose only when necessary Lambs The use of FECs Ewes at tupping Ewes around the time of lambing LSSC Ltd

Lambing Internal Parasitic Diseases in Lambs Coccidia Nematodirus Haemonchus Trichostrongylus Ostertagia Fluke Acute Chronic Spring Summer Autumn Winter

Treatment of Lambs Treatment based on regional information, assessment of risk factors and FECs Routine treatment at set ages to be discouraged Consideration of the parasite species involved

Treatment of Lambs Monitoring Use of FECs Larval differentiation Investigation of illthrift

Faecal Egg Counts (FECs) Faecal egg counts (FECs) can give a useful guide to the level of parasitism in a flock of sheep At least 10 animals should be sampled A group is a flock of sheep of the same sex, age, reproductive status and treatment history, running in the same field The faeces from 10 sheep may be pooled but only at the laboratory

FEC Monitoring Collection of faeces Gather the group, hold quietly in one area, then gather faeces from the pasture Place faeces in airtight container and cool Deliver to laboratory within 48 hours

FEC Monitoring Price and availability A FEC test is available from a number of laboratories and veterinary practices VLA labs offer a pooled test (10 samples) for 15.60 + VAT

Development of Immunity Sheep develop immunity to most worms by the time they are 4-5 months of age Fit healthy ewes are not adversely affected by a worm burden (unless haemonchus is present).

Treatment of Ewes Pre-tupping No routine drenching of fit adult ewes pretupping Drench immature or lean ewes only For Haemonchus contortus - use closantel LSSC

Treatment of Ewes at Lambing Consider the need to dose ewes around lambing time use highly efficacious treatments leave some (10-20%) of ewes untreated treat well before the end of PPRI avoid exclusive use of moxidectin post -lambing LSSC

Treatment of Ewes at Lambing Fit ewes and/or those rearing singles do not have significantly raised egg outputs New research suggests that a high protein ration also reduces egg output in twin bearing ewes.

6. Select the Appropriate Anthelmintic Use narrow spectrum products where possible Avoid off-target use Rotate where appropriate Use persistent action carefully (MOX; closantel)

7. Preserve a Susceptible Worm Population The Dose and Move strategy is likely to select heavily for AR The surviving worms are resistant and contaminate the pasture with their eggs. Without the dilution effect of contaminated pasture the frequency of resistant genes in the free-living population can increase quickly. In theory, the cleaner the pasture, the faster the resistant-gene frequency increases.

Selection Pressure of Treat Dose and Move R S PS R

Clean Grazing RESISTANT

Preserving Susceptible Worms Two practical options: Part-flock treatment (leave 10-20% untreated) OR. Delay the move after treatment

Effect of Preserving Susceptible Worms R + R S R PS S PS

8. Reduce Dependence on Anthelmintics Use grazing management to reduce the challenge Rams bred for resistance / resilience LSSC Ltd